1. Field of the Invention
The present invention relates to a method for installing a stopper mechanism in a plastic fitting which is connected to a water main or the like, and an apparatus for accomplishing the same. Specifically, the apparatus of the present invention relates to an improved connector arrangement between a stopper control shaft and an external drive shaft, and to a new and improved stopper mechanism. The present invention further relates to a new and improved process for installing a plastic fitting and stopper therefor onto an existing water main or the like.
2. Description of the Prior Art
Pipes which are made out of PE, PVC and ABS plastic resins are commonly used to carry water and other noncorrosive liquids for both industrial and residential applications. In order to control the flow of fluids or gases through such pipes, it has been known to provide closure devices which are adapted for installation onto a existing pipe. Such closure devices are especially useful for controlling a break in the pipeline, or for installing branch lines to the main.
In order to install such a closure device, a fitting piece having an opening therein is secured to the desired section of pipe, and a drilling machine can be used to cut through the pipe beneath the opening in the fitting. A completion cap or plug may be provided in the fitting to seal the opening therein when it is not desired to use the closure device. When a closure device is inserted into the opening and within the pipe, a control or stopper shaft extends through the opening to control the position of the closure mechanism within the pipe. Various arrangements have been used to connect and/or disconnect the completion plug from the opening in the fitting.
One problem which has existed in relation to such prior art devices arises from the difficulty in gaining access to pipe sections which are buried far underground, or in other remote locations. In such instances, it was often difficult to perform the tasks of installing the fitting, removing the completion plug from the fitting and installing or removing the closure mechanism from within the fitting. Indeed, it might have been necessary to use separate elongated tools to perform each function.
Another disadvantage of such prior art devices was that the connection between the stopper shaft and an external drive mechanism would occasionally come loose or unscrew because of the relative and shifting torque therebetween.
From the above, it is clear that there has existed a long and unfilled need in the prior art for a stopper system and method for stopping plastic pipes which would solve the above discussed problems resulting from the inaccessability of remote pipes, and the problems which have existed in prior art connections between the stopper shafts of such assemblies and external drive mechanisms.